NRF52840 Zephyr ADC read issue

RE: NRF52840 Zephyr ADC read issue

Marte Myrvold — Fri, 06 Sep 2024 08:06:57 GMT

Hi,

This ticket is more than two years old. Please create a new ticket.

Best regards,
Marte

RE: NRF52840 Zephyr ADC read issue

mohammad alrefaie — Thu, 05 Sep 2024 11:46:56 GMT

hello sir
how you built the adc sample for nrf52840 dongle??
can you guide me please??

RE: NRF52840 Zephyr ADC read issue

ovrebekk — Mon, 28 Mar 2022 13:16:06 GMT

I finally got some time to run some power consumption tests using the ADC driver, and using the adc_sample() function I don't seem to need to do anything in order to get low power consumption (other than disable logging in the application). When I sample the ADC at a slow rate it has very little impact on overall system power, and the sleep currents seem to be unchanged:

devzone.nordicsemi.com/.../adc_5F00_low_5F00_power.zip

Could you try it out and see if it works for you as well?

Regarding Zephyr threads it is important not to get them mixed up with the Thread wireless protocol ;)

The easiest way to create a thread is to use the K_THREAD_DEFINE macro, then you can create and start a thread with a single line of code:

// Define the thread function
void my_thread_func(void)
{

}

// Initialize and start the thread
K_THREAD_DEFINE(my_thread, 1024, my_thread_func, NULL, NULL, NULL, 5, 0, 0);

Best regards
Torbjørn

RE: NRF52840 Zephyr ADC read issue

thanosPr — Mon, 28 Mar 2022 11:24:09 GMT

Hi,

I deleted the "io-channels = <&adc 0>" in overlay file, only status exists in there.

Let me insert my new modified code about adc.

#include <zephyr/types.h>
#include <stddef.h>
#include <sys/printk.h>
#include <sys/util.h>

#include <device.h>
#include <devicetree.h>
#include <drivers/adc.h>
#include <drivers/gpio.h>

#define ADC_RESOLUTION		    10
#define ADC_GAIN			    ADC_GAIN_1_2
#define ADC_REFERENCE		    ADC_REF_INTERNAL
#define ADC_ACQUISITION_TIME	ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40)

#define ADC_CHANNEL_AIN0       0


#define NUM_OF_SAMPLES          128
#define VOLTAGE_DIVIDER_RATIO   0.2474   // R1=10k, R2=3.3K
#define VOLTAGE_DROP_PNP        30

const struct device *adc_dev;


uint32_t adcBuffer[NUM_OF_SAMPLES] = {0};
const float voltageDividerRatio = VOLTAGE_DIVIDER_RATIO;
const float voltageDropPNP = VOLTAGE_DROP_PNP;

static enum adc_action sample_with_interval_callback(struct device *dev, const struct adc_sequence *sequence, uint16_t sampling_index)
{   
    return ADC_ACTION_FINISH;
}

struct adc_sequence_options adcOptions = 
{
    .callback = sample_with_interval_callback,
};

static struct adc_channel_cfg adcConfig = 
{
	.gain             = ADC_GAIN,
	.reference        = ADC_REFERENCE,
	.acquisition_time = ADC_ACQUISITION_TIME,
	.channel_id       = ADC_CHANNEL_AIN0,
#if CONFIG_ADC_CONFIGURABLE_INPUTS
	.input_positive   = 1, 
#endif
};

const struct adc_sequence sequence = 
{
	    .options     = &adcOptions,				// extra samples and callback
		.channels    = BIT(ADC_CHANNEL_AIN0),	// bit mask of channels to read
		.buffer      = adcBuffer,		        // where to put samples read
		.buffer_size = sizeof(adcBuffer),
		.resolution  = ADC_RESOLUTION,		    // desired resolution
};
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
bool initializeADC(uint8_t channel)
{
    int adcInitError;
    
    adc_dev = DEVICE_DT_GET(DT_NODELABEL(adc));
    if(adc_dev == NULL)
    {
        return false;
    }   
    
    adc_dev = device_get_binding(DEVICE_DT_NAME(DT_NODELABEL(adc)));
    if(adc_dev == NULL)
    {
        return false;
    }

      return true;
}
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
void setADCenable(void)
{
     gpio_pin_set(adc_enable_dev, ADC_IO_PIN, 1);
}
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
void clearADCenable(void)
{
     gpio_pin_set(adc_enable_dev, ADC_IO_PIN, 0);
}
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
uint32_t getADCrawValue(void)
{
    int adcReadErr = 0;

    adcReadErr = adc_read(adc_dev, &sequence);
    if(adcReadErr == 0)
    {
        return adcBuffer[0];
    }
    return 0;
}
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
uint32_t readBatteryVoltage(void)
{
    uint32_t adcRaw = 0;
    uint32_t adcReading = 0;    
    
    for(int i=0; i<NUM_OF_SAMPLES; i++)
    {
        adcRaw = getADCrawValue();
        adcReading += adcRaw;
    }
    adcReading /= NUM_OF_SAMPLES;
    
    int32_t adc_vref = adc_ref_internal(adc_dev);

    adc_raw_to_millivolts(adc_vref, ADC_GAIN, 10, &adcReading); 

    adcReading += VOLTAGE_DROP_PNP;

     return adcReading * 4;
}

About creating a thread, you could use the below commands:

#define TEST_MGR_STACK 2048
struct k_thread test_mgr;

extern void test_task(void *, void *, void *);

K_THREAD_STACK_DEFINE(test_mgr_area, TEST_MGR_STACK);
void main(void)
{
    k_thread_create(&test_mgr, test_mgr_area, K_THREAD_STACK_SIZEOF(test_mgr_area), test_task, NULL, NULL, NULL, MY_PRIORITY, 0, K_NO_WAIT);
}

RE: NRF52840 Zephyr ADC read issue

yoyou — Mon, 28 Mar 2022 03:45:50 GMT

Hi,

NCS1.9.1, nRF52840DK,Windows10 X64, VSCode,

i've follow you,and adc_read() function returns -22 error.

How did you solve this problem? add thread?

#include <zephyr.h>
#include <device.h>
#include <drivers/gpio.h>
#include <sys/util.h>
#include <sys/printk.h>
#include <inttypes.h>
#include <drivers/adc.h>


#define ADC_RESOLUTION		    12
#define ADC_GAIN			    ADC_GAIN_1
#define ADC_REFERENCE		    ADC_REF_INTERNAL
#define ADC_ACQUISITION_TIME	ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 40)
#define ADC_CHANNEL_AIN0       0

#define ADC_IO_LABEL            DT_GPIO_LABEL(DT_ALIAS(gpiocus1), gpios)
#define ADC_IO_PIN	            DT_GPIO_PIN(DT_ALIAS(gpiocus1), gpios)

const struct device *adc_dev;
const struct device *adc_en_dev;


uint32_t sample_buffer[10] = {0};


static struct adc_channel_cfg adcConfig = 
{
	.gain             = ADC_GAIN,
	.reference        = ADC_REFERENCE,
	.acquisition_time = ADC_ACQUISITION_TIME,
	.channel_id       = 1, // gets set during init
	.differential	  = 0,
// #if CONFIG_ADC_CONFIGURABLE_INPUTS
	// .input_positive   = 0, // gets set during init
// #endif
};

const struct adc_sequence sequence = 
{
	    .options     = NULL,				// extra samples and callback
		.channels    = BIT(ADC_CHANNEL_AIN0),		// bit mask of channels to read
		.buffer      = sample_buffer,		// where to put samples read
		.buffer_size = sizeof(sample_buffer),
		.resolution  = ADC_RESOLUTION,		// desired resolution
		.oversampling = 0,					// don't oversample
		.calibrate = 0						// don't calibrate
};
//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
bool adc_init(uint8_t channel)
{
    int adcInitError;
    
    adc_dev = DEVICE_DT_GET(DT_NODELABEL(adc));
    if(adc_dev == NULL)
    {
 		printk("adc_init fail 1\n");
       	return false;
    }

    adc_dev = device_get_binding(DEVICE_DT_NAME(DT_NODELABEL(adc)));
    if(adc_dev == NULL)
    {
		printk("adc_init fail 2\n");
        return false;
    }

    adcConfig.channel_id = channel;
    adcInitError = adc_channel_setup(adc_dev, &adcConfig);
    if(adcInitError)
    {
		printk("adc_init fail 3\n");
        return false;
    }
	printk("adc_init done\n");

    return true;
}

//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
uint32_t main(void)
{
	adc_init(0);
    int readBatteryVoltageError = 0;

    readBatteryVoltageError = adc_read(adc_dev, &sequence);
    if(readBatteryVoltageError == 0)
    {
 		printk("readBatteryVoltage: %d \n",sample_buffer[0]);
		return sample_buffer[0];
    }
	printk("readBatteryVoltage error: %d \n",readBatteryVoltageError);

    return 0;
}

i cant not find know how to create thread

Thread protocol — Zephyr Project Documentation (nordicsemi.com)

Best Regards

RE: NRF52840 Zephyr ADC read issue

ovrebekk — Fri, 18 Mar 2022 16:50:30 GMT

Very good question, I have looked around for a power optimized ADC sample but can't seem to find any.

I will have to continue my search next week and get back to you 🙂

Best regards
Torbjørn

RE: NRF52840 Zephyr ADC read issue

thanosPr — Thu, 17 Mar 2022 11:52:24 GMT

Thanks ovrebekk for your anwser.

I have completed succesfully adc reading, but i am trying to disable it in order to reduce consumption.

How can i do that?

RE: NRF52840 Zephyr ADC read issue

ovrebekk — Thu, 17 Mar 2022 11:34:58 GMT

Hi Thanos

From where do you call the readBatteryVoltage() function?

The adc_read() function can not be called from an interrupt context, so it is important to make sure you call readBatteryVoltage() from thread context for this code to work.

Best regards
Torbjørn